﻿//using System;
//using System.Collections.Generic;
//using System.Linq;
using System.Text;
class Program
{
    public static void Main(String[] args)
    {
        StringBuilder sb = new StringBuilder();
        sb.Append("string1");
        sb.AppendLine("string2");
        sb.Append("string3");
        string s = sb.ToString();
        Console.WriteLine(s);
    }
}